Chucking means for drill bits



Jan. 23, 1945.

J. F. M CARTHY, JR

CHUGKING MEANS FOR DRILL BITS Filed Sept. 7, 1942 3 Sheets-Sheet l INVENTOR 6 Jugs E M Emm JR.

/ ATTORNEYS Jan, 23, 1945. J MCCARTHY, J 2,368,077

CHUCKING MEANS FOR DRILL BITS Filed Sept. 7, 1942 3 Sheets-Sheet 2 44 FIG. 2

5 I H 8 /2 26 x I 1 42 I 24 I a w- I II .22 l I I I! l /0 I I; I 44 aa ji INVENTOR Jgyss M GART/mJ/a v. A ORNEYS Q- Jain- 1945- J. F. M CARTHY. JR

CHUCKING MEANS FOR DRILL BITS 3 #k a Y, m m cw n B m RA r 6 00 R m m 0 S E M n V 3 A mt S 5 MM J Filed Sept. 7, 1942 Patented Jan. 23, 1945 UNITED STATES PATENT OFFICE CHUCKING MEANS FOR DRILL BITS James F. McCarthy, J12, Wallace, Idaho E Application September 7, 1942, Serial No. 457,563

3 Claims.

This invention relates to a chucking means for drill bits, and more particularly pertains to means for actuating said chucking means to clamp a drill bit when presented to a surfacing tool.

' In my United States Patent No. 2,268,714, is-

sued January 6, 1942, entitled Tool sharpening and gauging machine, I have shown a mechanism designed for conditioning or reconditioning rock drill bits. In this machine the drill bit is mounted upon a bit holder and chucking means including a clamping head is brought into engagement with the cutting face of the drill bit for clamping a drill bit and for rotating it during the gauging operation. According to this prior development, the actuation of the chucking means was manual and required an operator of such a machine to perform a definite operation in order to obtain-the desired clamping function. Since drill bit sharpening is a process which it is highly desirable to perform with the minimum of time and a minimum expenditure of physical force, the elimination of a single step in the oper-' ation of the machine is much to be desired. When elimination of a step reduces the physical demand upon the operator or workman, the entire operation can be speeded, the work can be performed with greater accuracy and efficiency, and the resetting of the mechanism for various types and sizes of drill bits can be readily ac- 'complished.

Having in mind the foregoing condition of the prior drill bit sharpening machinery, it is an object of my invention to provide means for actuating chucking means in such a machine to clamp a bit upon movement of the chucking means to present a work piece to a surfacing tool.

1.-Another object of my invention is to provide chuck actuating means of the type described which will readily adapt itself to varying sizes and heights of drill bits being clamped by the thus actuated chucking means. A still further and more specific object of my invention is the provision, in a drill bit sharpen- ,ing machine of the type described, of chuck actuating means that operates automatically upon swinging movement of the bit holder to a gauging position.

The foregoing objects and others ancillary .lthereto I preferto accomplish as follows:

i According to a preferred embodiment of my invention, 1 associate a stop or drag link with a being swung at the same time.

manner that swinging movement of the clamp head causes the drag link to bring the clamping head into clamping position upon the cutting face of a drill bit. This retains the bit between the clamp head and a bit holder, which is also Under certain conditions, the drag link is adapted to have its overall length varied for accommodating different sizes of drill bits, and in addition, a certain resiliency is provided so that minor variations in the operating conditions will bemet without the placing of undue strains and stresses upon'the parts of the mechanism.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a Figure 2 is a vertical sectional View taken 'on line 2-2 of Figure 1,

Figure 3 is a face elevational view of the chuck ing mechanism,

Figure 4 is a detail view illustrating themanner of presenting a drill bit to a sharpening wheel,

Figure 5 is a detail side view illustrating the manner of presenting a drill bit to a gauging wheel,

Figure 6 is a sectional view taken on line B of'Figure 3, and

Figure '7 is a side eleva'tional view illustratin the chuck actuating operation, with portions broken away for convenience of illustration.

A drill bit sharpening machine, to overcome the defects hereinabove enumerated, must have at least two totally distinct characteristics; it must be'capable of operating automatically without attention on the part of an operator of such a machine and it must also provide a positive and efiective clamp for the chucking operation to the end that the drill bit will be firmly maintained pertinent parts 01 a drill bit sharpening machine.

Such a machine comprises a. base l0 having mounted thereon a motor l2 for the rotary operation of a sharpening wheel l4, here shown as enclosed in the housing l6. The wheel l4, more specifically, is a double faced mill wheel that is caused to rotate on a horizontal axis. The drill bit [8 is presented to the wheel I4 so that the pointed nose is interposed between the sides of adjacent drill bit teeth to resurface a cutting face of each tooth. For presenting the drill bit to the sharpening and gauging wheel (the latter to be described hereafter), I employ a bit holder which is secured to the horizontal shaft 22 journaled in bearings 24, 24. A lever 26 also secured to the shaft permits the latter to be rocked manually to swing the bit holder as desired.

When a drill bit has been properly conditioned upon its cutting face, it is next presented to a gauging wheel such as the bevel mill wheel 28 which is rotated about an upright axis by the motor 30 mounted on the offset portion 3| of the base H). The wheel 28 is positioned in the path of a bit mounted upon the swinging bit holder 28, as can be seen in Figures 5 and 7. In presenting the drill bit or work piece to the wheel 28 it is desirable that the drill bit be clamped to the bit holder by a chucking means to retain it in place and also to permit its rotation for the annular surfacing of the gauge facer.

Mounted for swinging motion upon shaft 22 is the clamp arm 32 which has slidably mounted thereon the bushing 34 that is ordinarily pressed outward of the arm by means of a spring 36. Offset from bushing 34 is a clamp head journal 38 supported by the web 39 and in which is mounted for rotation the spindle 40. On its lower end spindle 40 has the clamp head 42 and on its upper end the crank 44, whereby manual rotation of the spindle is obtained. It will be seen that, upon sliding movement; of the bushing 34,

the clamp head 42 may be presented to the.

toothed face of a drill bit to engage it for rotary motion and to clamp it to the bit holder.

Bushing 34 has a bracket 46 to which is coupled the drag link 48. Link 48 is inserted into the bushing 50 and a spring 54 mounted on said link 48 between the head 52 and the upper end of bushing 50 provides a degree of resiliency at this point. An enlarged and interiorly threaded portion of the bushing 50, designated by the numeral 56, is fitted over the bushing 58 which is pivotally secured at 60 to the anchor block 62 on base In. The drag link, having its center of swinging movement spaced to the rear of the axis of shaft 22 about which arm 32 swings, produces a dragging motion upon the bushing 34 when the arm 32 and the bit holder 20 is swung to present the bit to a wheel 28.

Lever 26 has on its lower end a lug 64 which contacts a lug 66 for the gauging operation, as shown in Figure 6.

Thus it can be seen that manual operation of the lever 26 to the rear will present a drill bit on the bit holder to the wheel l4. The depth of the cut'taken in fiuting or facing the teethof the drill bit is limited by the set of the stop 27 against which lever 26 abuts as shown in Figure 1. When it is desired to gauge such a bit and the lever 26 is drawn forwardly, the lugs 64 and 66 come into contact with each other and the arm 32 will be engaged and swung about shaft 22. Since the drag link 48 is anchored at its end, its point of joinder to bracket 46 will describe a path that intersects the path that would otherwise have been described by bushing 34 had the two elements not been Joined. The clamping head 42 is thus drawn toward the bit holder and a drill bit thereon to engage and clamp the same. When the arm 32 is permitted to reassume position shown in Figure 1 the spring 36 will return the bushing 34 to its normal position on the end of shaft 32 and unclamp the drill bit.

When the drill bit is presented to the gauge miller 28 the stop bolt 68 comes into contact with the stop 29 in its path and permits the drill bit to be presented to wheel 28 only a predetermined amount. The amount of cutting permitted here is dependent upon the size and height of the drill bit.

.Under such conditions where various heights of drillbits are to be gauged, the length of the drag link is increased or shortened as desired by turning bushing 50 to cause relative adjustment between it and the bushing 58 to shorten or lengthen the link and to vary the clamping movement of the head.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim:

1. In a drill bit sharpening mechanism, a base having a pivot pin horizontally mounted thereon, an arm mounted on said pin to swing radially thereabout, chucking means offset from and slidably mounted upon said arm, a drag link between said chucking means and said base on that side of the arm away from its radial path of swing to cause the chucking means to be drawn axisward when the arm is swung, and a bit holder arm mounted upon .the pivot pin to swing in a plane parallel to said arm in alignment with the offset chucking means.

2. In a drill bit sharpening mechanism, a base having a pivot pin horizontally mounted thereon, an arm mounted on said pin to swing radially thereabout, chucking means offset from and slidably mounted upon said arm, spring mean urging said chucking means outward on said arm, a drag link between said chucking means and said base on that side of the arm away from its radial path of swing to cause the chucking means to be drawn axisward against said spring means when the arm is swung, and a bit holder arm mounted upon the pivot pin to swing in a plane parallel to said arm in alignment with the offset chucking means.

3. In a drill bit sharpening mechanism, a base having a pivot pin horizontally mounted thereon, an arm mounted on said pin to swing radially thereabout, chucking means offset from and slidably mounted upon said arm, an extensible resilient drag link between said chucking means and said base on that side of .the arm away from its radial path of swing to cause the chucking means to be drawn axisward when the arm is swung, and a bit holder arm mounted upon the pivot pin to swing in a plane parallel to said arm in alignment with the offset chucking means, said drag link being of a length when contracted to limit swinging movement of the arm upon its return from swinging movement jointly with said bit holder arm to permit the latter to be moved independently of the former for a portion of its radial path.

JAMES F. MCCARTHY, JR. 

